Plate heat exchanger

ABSTRACT

IN A MULTIPLE-PASS HEAT EXCHANGER, A FLUID PASSAGEWAY OF DOUBLE-PIPE CONSTRUCTION IS PROVIDED, HAVING A THROUGH PASSAGE EXTENDING THROUGH A MAIN SUPPORT FRAME, A PLURALITY OF PLATES AND A REAR SUPPORT FRAME WHICH ARE LIMINATED AND CLAMPED TOGETHER AND OTHER PASSAGES, PREFERABLY CONCENTRIC OR COMPLEMENTARY TO THE THROUGH PASSAGE FOR ESTABLISHING THE SERIES CONNECTIONS OF THE MULTIPLEPASS RELATION, IT BEING SO ARRANGED THAT A FLUID PASSING THROUGH A FLUID CHANNEL ON THE MULTIPLE-PASS SIDE IS LED TO THE REAR END OF SAID FLUID PASSAGEWAY AND IS WITHDRAWN FROM THE FRONT SURFACE OF SAID MAIN SUPPORT FRAME THROUGH SAID FLUID PASSAGEWAY. OR, THE FLUID IS SUPLIED FROM SAID FLUID PASSAGEWAY AND WITHDRAWN FROM THE FRONT SURFACE OF THE MAIN SUPPORT FRAME THROUGH THE CHANNEL ON THE MULTIPLE-PASS SIDE.

p 20, 1971 MASAFUMI DOI 3,605,881

PLATE HEAT EXCHANGER Filed Aug. 27, 1969 6 Sheets-Sheet 1 INVENTOR \7 /-y .Do/

ATTORNEY Sept. 20; 1971 MASAFUMI no:

PLATE am sxcmem 6 Sheets-Sheet 2 Filed Aug. 27, 1969 t v\ g aw? INVENTOR wh m/ 0 BY M ATTORNEY Sept. 20, 1971 MASAFUMI 001 5 rum am axcmmem Filed Aug. 27, 1969 e Sheets-Shoot INVENT OR Mam P ATTORNEY p 20, 1971 MASAFUMI 00! 3,605,881

PLATE HEAT EXOHANGER Filed Aug. 27. 1969 6 Sheets-Sheet 4 INVENIOR M4 P 4/!1/ Do/ ATTORNEY p 1971 MASAFUM! no:

PLATE HEAT EXCHANGER 6 Shoals-Shoot 5 Filed Aug. 27. 1969 QMQ Q INVENTOR N Nam Fu/v/ 1 0/ ATTOR N EY P 0, 1971 MASAFUMI DOI 3505,88

nus nan axcmwenn Filed Aug. 27, 1969 6 Sheets-Shoot c 1 NV ENT OR 7 fJ4/ l/M/ BY 2%6/ Z W ATTORNEY Patented Sept. 20, 1971 3,605,881 PLATE HEAT EXCHANGER Masafumi Doi, Daito-shi, Japan, assignor to Hisaka Works, Limited, Higashi Osaka-shi, Japan Filed Aug. 27, 1969, Ser. No. 853,366

Claims priority, application Japan, Sept. 5, 1968,

Int. Cl. F28b 3/00 U.S. Cl. 165-167 Claims ABSTRACT OF THE DISCLOSURE In a multiple-pass heat exchanger, a fluid passageway of double-pipe construction is provided, having a through passage extending through a main support frame, a plurality of plates and a rear support frame which are laminated and clamped together and other passages, preferably concentric or complementary to the through passage, for establishing the series connections of the multiplepass relation, it being so arranged that a fluid passing through a fluid channel on the multiple-pass side is led to the rear end of said fluid passageway and is withdrawn from the front surface of said main support frame through said fluid passageway. Or, the fluid is supplied from said fluid passageway and withdrawn from the front surface of the main support frame through the channel on the multiple-pass side.

BACKGROUND OF THE INVENTION (a) Field of the invention This invention relates to a structure for withdrawing fluids in a plate heat exchanger.

(b) Description of the prior art In multiple plate heat exchangers, if the volume rates of flow and the cross-sectional areas of the channels for two dissimilar fluids are respectively equal, the liquid velocities in the respective fluid channels are equal. In this case, as shown in FIG. 1, the one-pass system is employed for each fluid channel and two dissimilar fluids may be passed countercurrent to each other. Then, the liquid velocity in the respective fluid channels a and b are naturally equal to each other.

If, however, the volume rates of flow are different, the liquid velocity on the lower volume rate side is naturally slower. Therefore, the rate of occurrence of scale in the fluid channel on the lower volume rate side is higher than that in the other fluid channel. In general, heat transfer fillm coefficient (h) for two dissimilar fluids is proportional to the n power of liquid velocity V (where n: 0.6 -0.8

This is expressed in the following formula. hocC'V C: coefficient. Overall heat-transfer coefficient (U) is found in the following formula;

nib.

wherein 11 is the heat transfer film coefficient of fluid to be cooled, wherein h is the heat transfer film coefiicient of cooling fluid. As for heat-transfer area (A),

wherein q is the exchange heat quantity, At is the logarithmic mean temperature difference between two fluids. It is seen from the above formula that heat-transfer area (A) decreases with increasing overall heat transfer coefficient (U). In short, in plate heat exchangers and the like, it is preferable that the liquid velocity of two dissimilar fluids be equal to each other. As for methods of allowing fluids with different volume rates of flow to be passed countercurrent to each other, a system shown in FIG. 2 is known. Thus, if the cross-sectional areas of the fluid channels are equal to each other and the volume rate of flow in one fluid channel is two times as high as that in the other, then the liquid velocity in the respective channels c, d, e and f are equal to each other. Therefore, it becomes possible to make the rate of occurrence of scale in the channels on the lower volume rate side equal to that in the channels on the higher volume rate side and optimize the overall heat-transfer coefficient.

However, the plate heat exchanger employing the onepass and two-pass system shown in FIG. 2 has the following disadvantages in the structure and handling. The reason therefor will be described below.

In multiple plate heat exchangers, during operation, gaskets interposed between the plates tend to age due to high temperature high pressure fluids passing between the plates or to be displaced as they are outwardly pushed by such fluids, resulting in frequent leakage of fluids. Therefore, after a predetermined period of operation, it is necessary to tighten up the laminated plates.

The tightening up of the laminated plates would naturally result in a variation in the lamination width. Since the plate heat exchanger of one-pass system generally shown in FIG. 1 has inlets 2 and 3 and outlets 4 and 5 for the respective fluids positioned in the surface of a main support frame 1 as a consequence of the structure, it follows that even if the laminated width varies, the main support frame itself will not move, it is possible to tighten up the plates while the pipings connected to the inlets 2, 3 and outlets 4, 5 remain stationary. That is to say, it is only the individual plates and a rear support frame 6 that trnove upon tightening up. However, in a plate heat exchanger wherein one of the channels is of two-pass system and the other is of one-pass system as shown in FIG. 2, it follows that a fluid outlet 7 on the two-pass side is positioned in the surface of a rear support frame 8. Therefore, in the case of the plate heat exchanger of this system, the tightening up of the plates is impossible unless a fixed piping connected to the fluid outlet 7 of the rear support frame 8 is removed each time tightening up is to be effected. After tightening up, a clearance would exist between the outlet 7 and (fixed piping due to the movement of the rear support frame 8 as described above, and this problem has to be solved by some suitable method. In addition, in FIG. 2, the numeral 9 denotes a main support frame; 10 and 11, inlets for fluids; and 12, an outlet for the other fluid.

SUMMARY OF THE INVENTION The present invention provides an improved multiple plate heat exchanger characterized in that there is provided a fluid passageway of double-pipe construction, having a through passage extending through a main support, through a plurality of plates and through a rear support frame and having other passages concentric or complimentary to the through passage for establishing the series connections of the multiple pass relation, the arrangement being such that a fluid passing through a channel on the multiple-pass side is led to the rear end of said fluid passageway and withdrawn from the front surface of the main support frame through said fluid passageway or that the fluid is supplied from said fluid passageway and withdrawn from the front surface of the main support frame through the multiple-pass side.

3 BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings illustrating preferred embodiments of the present invention:

FIGS. 1 and 2 are explanatory views of known plate heat exchangers, FIG. 1 showing a heat exchanger whose fluid channels for two dissimilar fluids each are of the one-pass system, FIG. 2 showing a heat exchanger in which one fluid channel is of the one-pass system and the other fluid channel is of the two-pass system;

FIGS. 3 through 7 are explanatory views of a plate heat exchanger of one-pass and two-pass system according to the present invention, FIG. 3 being a front view, FIG. 4 being a side view, FIG. 5 being a section on the line VV of FIG. 3, FIG. 6 being a section on the line VIVI of FIG. 3, FIG. 7 being an exploded explanatory view thereof;

FIG. 8 is a schematic view wherein the heat exchanger shown in FIGS. 3 through 7 is changed into one of onepass and three-pass. system;

FIGS. 9 through 11 shows a further embodiment of the invention, FIG. 9 being a section taken through a portion corresponding to the line VIVI of FIG. 3, FIG. 10 being an exploded explanatory view, FIG. 11 being an explanatory view showing an example of a gasket.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to a preferred embodiment of a plate heat exchanger shown in FIGS. 3 through 7, this novel article is a plate heat exchanger with passageways of the same sectional area, wherein in effecting heat exchange between two dissimilar fluids with different volume rates of flow, a fluid on the multiple-pass side is led to the front surface of a main support frame, and inlets and outlets for the respective fluids are provided in the front surface of the main support frame.

In FIGS. 3 and 4, a plurality of plates 13 are laminated and stacked between a main support frame 9 and a rear support frame 8 by means such as conventional gaskets 14 as shown in FIG. 5.

The plates 13 and rear support frame 8 are clamped against the rear surface of the main support frame 9 by means of clamping metal fixtures 15. In addition, the

plates and rear support frame are disposed between upper and lower main frames 16 and 17.

In this manner passageways for two dissimilar fluids A and B are formed between individual plates.

The arrangement of the fluid channels for the two dissimilar fluids A and B will now be described in detail with reference to FIGS. 5 and 6.

FIG. 5 is a lay out view of channels corresponding to channels and e on the larger volume rate side in FIG. 2. The fluid A flows from an inlet 11 through a lower horizontal channel g to branch off to flow upwardly through vertical channels h formed by the plates and then collects in an upper horizontal channel i and reaches an outlet 12.

That is to say, the fluid A all flows upwardly into the channel h as it branches off. Thus it is flowing in accordance with the one-pass system.

On the other hand, FIG. 6 is a layout view of channels corresponding to the channels 0! and f on the lower volume rate side in FIG. 2. The structure thereof is as follows.

Vertical channels for the fluid B are divided into two group connected; a group of vertical channels in the left-hand half of the figure called first channels 1' and a group of vertical channels in the right-hand half of the figure are called the second channels k. Thus, the fluid B flowing in from the inlet 10 passes through an upper first horizontal channel l to branch off to flow downwardly through the first vertical channels j, passing through a lower horizontal channel a series connection m to reach the adjoining second vertical channels k, then branching off to flow upwardly through said second vertical channels k to be collected in an upper second horizontal channel n, finally reaching the outlet 7 in the rear support frame 8. The fluid B collected in the outlet 7 is led through a joint pipe 18- into a fluid passageway 19 extending through and lying between the two support frames 9 and 8 and reaches an outlet 20 in the main support frame 9.

The arrangement of the fluid passageway 19 which is the gist of the invention will now be described. The fluid passageway 19 shown in FIGS. 6 and 7 extends through the respective central regions of fluid channel openings 21 in the plates forming the lower horizontal channel m for the fluid B, and the lower horizontal channel m is formed as a passageway 22 of annular cross-section around the fluid passageway 19. In addition, no annular passageway is provided between the plates forming channels for the fluid A. In other words, referring to FIGS. 6 and 5, the heat exchanger comprises an assembly including as elements (a) the main support frame 9, (b) a plurality of plates 13, (c) a rear support frame 8, ((1) means 14 serving to space said plates from each other and from the main and rear support frames to provide fluid passages h and k therebetween, and (e) means (15, FIG. 4) clamping the elements (b), (c) and (d) to the element (a); the assembly has means. (shown as openings 11 and 12 and gaskets 14, FIG. forming a first fluid passage having an inlet and an outlet and 11) through said main support frame 9, put into communication with each other through alternate ones h of said fluid passages h and k (FIG. 5) and means (shown as openings 10 and and gaskets 14, FIG. 6) forming a second fluid passage having inlet and outlet passages (10 and 20) through said main support frame 9, and put into communication with each other through the remainder (k) of said fluid passages (h) and (k); the assembly being particularly characterized in that the second fluid inlet and outlet passages 10, 20, are put into communication with each other through first the passages (k) connected to have no less than two thereof in series with one another to form a multiple pass channel I, m, n (FIG. 6) with one of its ends (I) proximate to the main support frame 9 and the other of its ends it proximate to the rear support frame 8, and second, connecting means 19, 2:2 of double pipe construction simultaneously forming said series connections m and, in juxtaposed relation thereto, a passageway 18-19 constituting the connection between the end of the multiple pass channel n and the second fluid passage 20 through the main support frame 9. In this arrangement, as above noted the double pipe construction comprises means 19 forming a central pipe constituting part of the passageway 18, 19, 20 and means 14 forming pipe sections concentric thereto constituting the series connection m, and the rear supporting frame 8 is provided with second fluid passages therethrough interconnected by the external pipe 18 and constituting part of said passageway 18, 19, 20.

FIG. 8 shows a plate heat exchanger wherein the fluid B on the higher volume rate side flows in accordance with a three-pass system, or odd number-pass system whose number of passes is greater than one. In this case, it becomes unnecessary to provide a joint pipe fixedly secured to the rear support frame 8, since a third channel 0 serves also as a joint pipe. Therefore, the fluid passageway 19 is opened to the surface of a front plate 13 forming the third channel 0. That is to say, the fluid channel 19 is formed between the main support frame 9 and the front plate 13" of the third channel 0. The remaining structure is the same as in two-pass system.

FIGS. 9 through 11 show a further embodiment of a double pipe construction simultaneously providing the series connections between the passes and the fluid passageway 19. The double pipe construction is arranged in the following manner: In stacking and clamping the plates between the main support frame 9 and rear support frame 8, two types of gaskets 2.9 and are used to form a lower horizontal passageway m and fluid passageway 19 for the fluid B at the same time.

The aforementioned channel arrangement will now be described in more detail with reference to FIGS. and 11. Openings 31 are provided in the main support frame 9, plate 13 and rear support frame 8 for forming the fluid passageway 19. Between the particular plates forming the lower horizontal channel m, namely, plates 13 and 13 as shown in FIG. 11 there is interposed a circular gasket 29 internally divided into two parts by a partition plate 32. The gasket 29 divides the fluid channel openings 33 in the plates 13 and 13 into two complementary parts, and an upper divided opening 29 in the circular gasket 29 form the series connecting lower horizontal channel m. Further, between the main support frame 9 and plate 13 between the plates 13 and 13 and between the plate 13 and rear support frame 8, there are interposed semi-circular gaskets 30 as shown in FIG. 11, and all the semi-circular gaskets 30 and the lower divided openings 29 in said circular gaskets 29 form the return passageway 19. In addition, openings 31 having the same shape as that of the semi-circular gasket may be provided in the main support frame 9, plates 13- and 13 and rear support frame 8, alternatively, a circular opening may be provided in each of them and a half section of such opening may be suitably closed. In addition, the gaskets shown in FIGS. 9 through 11 are only an embodiment of the present invention, and gaskets of other shape may also be used as long as the gasket shape satisfies the idea suggested in FIGS. 9 through 11.

The above description is directed to embodiments of the plate heat exchanger according to the present invention, and the number of plates, the number of channels on the multiple-pass side, the type such as vertical or horizontal type, etc. are optional. Further, the system shown in FIG. 8 may be applied to a plate heat exchanger with a return passageway arrangement in another embodiment.

As has so far been described above, according to the present invention, a main support frame can be provided with inlets and outlets for two dissimilar fluids. Therefore, the plate lamination can be easily tightened up or disassembled for cleaning, inspection or other purposes without the need of removing the piping. Further, the invention makes it possible to obtain a plate heat exchanger which has a minimum heat transfer area A and, a compact structure light in weight and which is inexpensive.

While there have been described herein what are at present considered preferred embodiments of the several features of the invention, it will be obvious to those skilled in the art that modifications and changes may be made without departing from the essence of the invention.

It is therefore to be understood that the exemplary embodiments thereof are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims and that all modifications that come within the meaning and range of equivalency of the claims are intended to be included therein.

I claim:

1. A multiple-plate heat exchanger comprising an assembly including as elements (1) a main support frame,

(2) a plurality of plates,

(3) a rear support frame,

(4) means serving to space said plates from each other and from said main and rear support frames to provide fluid passages therebetween, and

(5) means clamping said elements (2), (3) and (4) to said element D,

said assembly having (6) means forming a first fluid passage having an inlet and an outlet through said main support frame put into communication with each other through alternate ones of said fluid passages, and

(7) means forming a second fluid passage having inlet and outlet passages through said main support frame and put into communication with each other through the remainder of said fluid passages,

said assembly being particularly characterized in that (8) the second fluid inlet and outlet passages formed by said last named means are put into communication with each other through the remainder of said fluid passages connected to have no less than two thereof in series with one another to form a multiple pass channel with one of its ends proximate to the main support frame and the other of its ends proximate to the rear support frame, and through connecting means of double pipe construction simultaneously forming said series connections and, in juxtaposed relation thereto, a passageway constituting the connection between the end of the multiple-pass channel proximate to the rear support and a second fluid passage through said main support frame.

2. A multiple plate heat exchanger as claimed in claim 1, wherein said rear supporting frame is provided with second fluid passages therethrough interconnected by an external pipe and constituting a part of said passageway.

3. A multiple plate heat exchanger as claimed in claim 1, wherein the space between said rear supporting frame and the next adjacent plate constitutes a part of said passageway.

4. A multiple plate heat exchanger as claimed in claim 1, wherein the double pipe construction comprises means forming a central pipe constituting part of said passageway and means forming pipe sections concentric thereto constituting said series connections.

5. A multiple plate heat exchanger as claimed in claim 1, wherein the double pipe construction comprises means forming a part-cylindrical pipe constituting part of said passageway and means forming pipe sections complementary thereto constituting said series connections.

References Cited UNITED STATES PATENTS 2,937,856 5/1960 Thomson 167X 2,960,160 11/1960 Goodman 165-167X 3,106,243 10/1963 Knudsen 16 5-167 FREDERICK L. MATTESON, JR., Primary Examiner T. W. STREULE, Assistant Examiner 

